diff --git a/apps/desktop/src/components/editor/EditorSettingsDialog.vue b/apps/desktop/src/components/editor/EditorSettingsDialog.vue
index de45aa25c4..9a99098e58 100644
--- a/apps/desktop/src/components/editor/EditorSettingsDialog.vue
+++ b/apps/desktop/src/components/editor/EditorSettingsDialog.vue
@@ -359,7 +359,7 @@ import {
   type EditorSettingsDraftKey,
 } from "@/lib/settings/editorSettingsDraft";
 import { applyEditorSettingsDraftToRefs, type EditorSettingsDraftRefMap } from "@/lib/settings/applyEditorSettingsDraft";
-import { serializeSettingsTransfer, sortTransferCategories, transferCategoryForKey, type SettingsTransferCategoryId } from "@/lib/settings/settingsTransfer";
+import { pickTransferableDesktopSettings, serializeSettingsTransfer, sortTransferCategories, transferCategoryForKey, type SettingsTransferCategoryId, type SettingsTransferExtras, type TransferableDesktopSettings, type TransferableDesktopSettingsKey } from "@/lib/settings/settingsTransfer";
 import { useConnectionStore } from "@/stores/connectionStore";
 import { useQueryStore } from "@/stores/queryStore";
 import { effectiveDatabaseTypeForConnection } from "@/lib/database/jdbcDialect";
@@ -3939,9 +3939,17 @@ async function copyAppSupportInfo() {
 // --- Settings import / export (About page card) ---
 
 function buildSettingsExportPayload(): string {
-  return serializeSettingsTransfer(settingsStore.editorSettings, {
-    appVersion: props.appVersion || appSupportInfo.value?.appVersion || undefined,
-  });
+  return serializeSettingsTransfer(
+    settingsStore.editorSettings,
+    { appVersion: props.appVersion || appSupportInfo.value?.appVersion || undefined },
+    {
+      themeMode: themeMode.value,
+      // On web the desktop store only holds defaults (the switches are hidden),
+      // so exporting them would let a web-made file overwrite a desktop user's
+      // real tray/close preferences on import.
+      desktopSettings: isWeb ? undefined : pickTransferableDesktopSettings(settingsStore.desktopSettings),
+    },
+  );
 }
 
 // "Apply and export": reuse the regular apply flow so validation, persistence
@@ -3972,18 +3980,57 @@ function applyImportedEditorSettings(imported: Partial<EditorSettings>) {
   hasImportedSettingsPendingApply.value = true;
 }
 
+// Imported desktop preferences load into the same draft refs the settings
+// switches use, so the footer Apply (and its unapplied-changes protection)
+// covers them exactly like a manual toggle. The desktop section is skipped on
+// web: those switches have no meaning there.
+function applyImportedDesktopSettings(desktop: Partial<TransferableDesktopSettings>) {
+  if (isWeb) return;
+  if (desktop.show_tray_icon !== undefined) editShowTrayIcon.value = desktop.show_tray_icon;
+  if (desktop.quit_on_close !== undefined) editQuitOnClose.value = desktop.quit_on_close;
+  if (desktop.icon_theme !== undefined) editIconTheme.value = desktop.icon_theme;
+  if (desktop.debug_logging_enabled !== undefined) editDebugLoggingEnabled.value = desktop.debug_logging_enabled;
+  if (desktop.metadata_cache_max_memory_mb !== undefined) editMetadataCacheMaxMemoryMb.value = desktop.metadata_cache_max_memory_mb;
+  if (desktop.duckdb_worker_process_isolation !== undefined) editDuckDbWorkerProcessIsolation.value = desktop.duckdb_worker_process_isolation;
+  if (desktop.duckdb_worker_max_processes !== undefined) editDuckDbWorkerMaxProcesses.value = desktop.duckdb_worker_max_processes;
+  if (desktop.sidebar_table_page_size !== undefined) editSidebarTablePageSize.value = desktop.sidebar_table_page_size;
+}
+
+// The app-wide theme mode has no draft state: it applies immediately through
+// the same live path the theme buttons in the appearance tab use.
+function applyImportedExtras(extras: SettingsTransferExtras) {
+  if (extras.themeMode) setThemeMode(extras.themeMode);
+  const desktopKeys = Object.keys(extras.desktopSettings ?? {}) as TransferableDesktopSettingsKey[];
+  if (desktopKeys.length === 0) return;
+  applyImportedDesktopSettings(extras.desktopSettings ?? {});
+  hasImportedSettingsPendingApply.value = true;
+}
+
 // Categories whose draft values differ from the saved base AND are covered by
 // the imported file — these draft changes will be replaced by the import.
-function getDraftConflictCategories(imported: Partial<EditorSettings>): SettingsTransferCategoryId[] {
+function getDraftConflictCategories(imported: Partial<EditorSettings>, extras?: SettingsTransferExtras): SettingsTransferCategoryId[] {
   const changedKeys = new Set(Object.keys(editorSettingsPatchFromDraft(currentEditorSettingsDraft(), editEditorSettingsBase.value)));
   const conflicts = new Set<SettingsTransferCategoryId>();
   for (const key of Object.keys(imported)) {
     const category = transferCategoryForKey(key);
     if (category && changedKeys.has(key)) conflicts.add(category);
   }
+  if (extras?.desktopSettings && !isWeb && importedDesktopKeysTouchDraft(extras.desktopSettings)) conflicts.add("other");
   return sortTransferCategories(conflicts);
 }
 
+function importedDesktopKeysTouchDraft(desktop: Partial<TransferableDesktopSettings>): boolean {
+  if (desktop.show_tray_icon !== undefined && editShowTrayIcon.value !== settingsStore.desktopSettings.show_tray_icon) return true;
+  if (desktop.quit_on_close !== undefined && editQuitOnClose.value !== settingsStore.desktopSettings.quit_on_close) return true;
+  if (desktop.icon_theme !== undefined && editIconTheme.value !== settingsStore.desktopSettings.icon_theme) return true;
+  if (desktop.debug_logging_enabled !== undefined && editDebugLoggingEnabled.value !== settingsStore.desktopSettings.debug_logging_enabled) return true;
+  if (desktop.metadata_cache_max_memory_mb !== undefined && editMetadataCacheMaxMemoryMb.value !== settingsStore.desktopSettings.metadata_cache_max_memory_mb) return true;
+  if (desktop.duckdb_worker_process_isolation !== undefined && editDuckDbWorkerProcessIsolation.value !== settingsStore.desktopSettings.duckdb_worker_process_isolation) return true;
+  if (desktop.duckdb_worker_max_processes !== undefined && editDuckDbWorkerMaxProcesses.value !== settingsStore.desktopSettings.duckdb_worker_max_processes) return true;
+  if (desktop.sidebar_table_page_size !== undefined && editSidebarTablePageSize.value !== (settingsStore.desktopSettings.sidebar_table_page_size ?? DEFAULT_SIDEBAR_TABLE_PAGE_SIZE)) return true;
+  return false;
+}
+
 function clearDebugLogs() {
   clearStoredDebugLogs();
   debugLogCopied.value = false;
@@ -13178,6 +13225,7 @@ LIMIT 100;</pre>
                 :build-saved-export-payload="buildSettingsExportPayload"
                 :build-applied-export-payload="buildAppliedExportPayload"
                 :apply-imported-settings="applyImportedEditorSettings"
+                :apply-imported-extras="applyImportedExtras"
                 :get-draft-conflict-categories="getDraftConflictCategories"
               />
 
diff --git a/apps/desktop/src/components/settings/SettingsTransferPanel.vue b/apps/desktop/src/components/settings/SettingsTransferPanel.vue
index b93ece59ba..6956549ca2 100644
--- a/apps/desktop/src/components/settings/SettingsTransferPanel.vue
+++ b/apps/desktop/src/components/settings/SettingsTransferPanel.vue
@@ -17,6 +17,7 @@ import {
   SETTINGS_TRANSFER_FORMAT_VERSION,
   type ParsedSettingsTransfer,
   type SettingsTransferCategoryId,
+  type SettingsTransferExtras,
   type SettingsTransferParseError,
 } from "@/lib/settings/settingsTransfer";
 
@@ -27,7 +28,8 @@ const props = defineProps<{
   buildSavedExportPayload: () => string;
   buildAppliedExportPayload: () => Promise<string | null>;
   applyImportedSettings: (imported: Partial<EditorSettings>) => void;
-  getDraftConflictCategories: (imported: Partial<EditorSettings>) => SettingsTransferCategoryId[];
+  applyImportedExtras: (extras: SettingsTransferExtras) => void;
+  getDraftConflictCategories: (imported: Partial<EditorSettings>, extras?: SettingsTransferExtras) => SettingsTransferCategoryId[];
 }>();
 
 const { t } = useI18n();
@@ -195,14 +197,19 @@ async function handleFileInputChange(event: Event) {
 }
 
 function handleImportedText(text: string, fileName: string) {
-  const result = parseSettingsTransferFile(text);
+  // The desktop section carries switches that only exist in the Tauri app;
+  // on web it is skipped so the preview lists only what will be applied.
+  const result = parseSettingsTransferFile(text, { includeDesktopSettings: isTauriRuntime() });
   if (!result.ok) {
     toast(translateParseError(result.error), 5000);
     return;
   }
   pendingImport.value = result.value;
   pendingImportFileName.value = fileName;
-  pendingImportConflicts.value = props.getDraftConflictCategories(result.value.editorSettings);
+  pendingImportConflicts.value = props.getDraftConflictCategories(result.value.editorSettings, {
+    themeMode: result.value.themeMode,
+    desktopSettings: result.value.desktopSettings,
+  });
   showImportConfirmDialog.value = true;
 }
 
@@ -233,10 +240,13 @@ function confirmImport() {
   const imported = pendingImport.value;
   if (!imported) return;
   props.applyImportedSettings(imported.editorSettings);
+  props.applyImportedExtras({ themeMode: imported.themeMode, desktopSettings: imported.desktopSettings });
   showImportConfirmDialog.value = false;
   pendingImport.value = null;
   pendingImportConflicts.value = [];
-  // The draft is not persisted yet; applying is still the user's job.
+  // The editor and desktop drafts are not persisted yet; applying is still
+  // the user's job. The theme mode applies immediately, like the theme
+  // buttons in the dialog.
   toast(t("settings.settingsTransferImportLoaded"));
 }
 </script>
diff --git a/apps/desktop/src/lib/settings/__tests__/settingsTransfer.spec.ts b/apps/desktop/src/lib/settings/__tests__/settingsTransfer.spec.ts
index 1a4ef09fc2..2209060426 100644
--- a/apps/desktop/src/lib/settings/__tests__/settingsTransfer.spec.ts
+++ b/apps/desktop/src/lib/settings/__tests__/settingsTransfer.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, it } from "vitest";
-import { DEFAULT_EDITOR_SETTINGS, type EditorSettings } from "@/stores/settingsStore";
+import { DEFAULT_DESKTOP_SETTINGS, DEFAULT_EDITOR_SETTINGS, type EditorSettings } from "@/stores/settingsStore";
 import { EDITOR_SETTINGS_DRAFT_KEYS } from "../editorSettingsDraft";
-import { buildSettingsTransferFilename, collectTransferCategories, parseSettingsTransferFile, serializeSettingsTransfer, SETTINGS_TRANSFER_FORMAT_VERSION, transferCategoryForKey } from "../settingsTransfer";
+import { buildSettingsTransferFilename, collectTransferCategories, parseSettingsTransferFile, pickTransferableDesktopSettings, serializeSettingsTransfer, SETTINGS_TRANSFER_FORMAT_VERSION, transferCategoryForKey } from "../settingsTransfer";
 
 function fileWith(editor: Record<string, unknown>, overrides: Record<string, unknown> = {}): string {
   return JSON.stringify({
@@ -13,6 +13,15 @@ function fileWith(editor: Record<string, unknown>, overrides: Record<string, unk
   });
 }
 
+function fileWithSections(sections: Record<string, unknown>): string {
+  return JSON.stringify({
+    formatVersion: SETTINGS_TRANSFER_FORMAT_VERSION,
+    app: { name: "dbx", version: "1.2.3" },
+    exportedAt: "2026-09-06T00:00:00.000Z",
+    settings: sections,
+  });
+}
+
 describe("settingsTransfer", () => {
   it("round-trips column comment placement as a data preference and rejects non-booleans", () => {
     const text = serializeSettingsTransfer({ ...DEFAULT_EDITOR_SETTINGS, dataGridColumnCommentsInInfoArea: true, dataGridTransposeMetadataInInfoColumn: true });
@@ -677,4 +686,125 @@ describe("settingsTransfer", () => {
     if (result.ok) expect(result.value.editorSettings.aiSqlApplyTargetMode).toBe("new");
     expect(parseSettingsTransferFile(fileWith({ aiSqlApplyTargetMode: "invalid" })).ok).toBe(false);
   });
+
+  it("round-trips the app theme mode and desktop preferences (#13166)", () => {
+    const desktopSettings = {
+      show_tray_icon: false,
+      icon_theme: "black",
+      quit_on_close: true,
+      debug_logging_enabled: true,
+      metadata_cache_max_memory_mb: 128,
+      duckdb_worker_process_isolation: true,
+      duckdb_worker_max_processes: 8,
+      sidebar_table_page_size: 500,
+    };
+    const text = serializeSettingsTransfer(DEFAULT_EDITOR_SETTINGS, {}, { themeMode: "dark", desktopSettings });
+    const result = parseSettingsTransferFile(text);
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.value.themeMode).toBe("dark");
+    expect(result.value.desktopSettings).toEqual(desktopSettings);
+    expect(result.value.categories).toContain("appearance");
+    expect(result.value.categories).toContain("other");
+  });
+
+  it("imports editor-only exports without theme mode or desktop preferences", () => {
+    const result = parseSettingsTransferFile(serializeSettingsTransfer(DEFAULT_EDITOR_SETTINGS));
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.value.themeMode).toBeUndefined();
+    expect(result.value.desktopSettings).toEqual({});
+  });
+
+  it("imports a file that only carries the appearance and desktop sections", () => {
+    const result = parseSettingsTransferFile(fileWithSections({ appearance: { themeMode: "system" }, desktop: { show_tray_icon: false } }));
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.value.editorSettings).toEqual({});
+    expect(result.value.themeMode).toBe("system");
+    expect(result.value.desktopSettings).toEqual({ show_tray_icon: false });
+    expect(result.value.categories).toEqual(["appearance", "other"]);
+  });
+
+  it("rejects invalid theme modes", () => {
+    const invalid = parseSettingsTransferFile(fileWithSections({ appearance: { themeMode: "blue" } }));
+    expect(invalid.ok).toBe(false);
+    if (!invalid.ok) {
+      expect(invalid.error.code).toBe("invalid-fields");
+      expect(invalid.error.detail).toContain("appearance.themeMode");
+    }
+    expect(parseSettingsTransferFile(fileWithSections({ appearance: { themeMode: "soft-dark" } })).ok).toBe(false);
+  });
+
+  it("rejects wrong-typed desktop values", () => {
+    const flag = parseSettingsTransferFile(fileWithSections({ desktop: { show_tray_icon: "yes" } }));
+    expect(flag.ok).toBe(false);
+    if (!flag.ok) expect(flag.error.detail).toContain("show_tray_icon");
+
+    const numeric = parseSettingsTransferFile(fileWithSections({ desktop: { metadata_cache_max_memory_mb: "128" } }));
+    expect(numeric.ok).toBe(false);
+  });
+
+  it("rejects desktop values the normalizer would clamp or replace", () => {
+    const clamped = parseSettingsTransferFile(fileWithSections({ desktop: { duckdb_worker_max_processes: 99 } }));
+    expect(clamped.ok).toBe(false);
+    if (!clamped.ok) expect(clamped.error.detail).toContain("duckdb_worker_max_processes");
+
+    const iconTheme = parseSettingsTransferFile(fileWithSections({ desktop: { icon_theme: "blue" } }));
+    expect(iconTheme.ok).toBe(false);
+
+    const floored = parseSettingsTransferFile(fileWithSections({ desktop: { sidebar_table_page_size: 0 } }));
+    expect(floored.ok).toBe(false);
+
+    const belowMinimum = parseSettingsTransferFile(fileWithSections({ desktop: { metadata_cache_max_memory_mb: 5 } }));
+    expect(belowMinimum.ok).toBe(false);
+  });
+
+  it("ignores unknown and excluded keys in the desktop section", () => {
+    const result = parseSettingsTransferFile(fileWithSections({ desktop: { quit_on_close: true, driver_store_dir: "C:\\evil", close_action_prompted: true, injected: "x" } }));
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.value.desktopSettings).toEqual({ quit_on_close: true });
+  });
+
+  it("keeps device-specific desktop keys out of the serialized payload", () => {
+    const text = serializeSettingsTransfer(
+      DEFAULT_EDITOR_SETTINGS,
+      {},
+      {
+        desktopSettings: pickTransferableDesktopSettings({ ...DEFAULT_DESKTOP_SETTINGS, driver_store_dir: "C:\\drivers", quit_on_close: true }),
+      },
+    );
+    expect(text).not.toContain("driver_store_dir");
+    expect(text).not.toContain("saved_sql_sync_dir");
+    expect(text).not.toContain("close_action_prompted");
+    expect(text).toContain("quit_on_close");
+  });
+
+  it("rejects non-object appearance and desktop sections", () => {
+    expect(parseSettingsTransferFile(fileWithSections({ desktop: [1] })).ok).toBe(false);
+    expect(parseSettingsTransferFile(fileWithSections({ appearance: "dark" })).ok).toBe(false);
+  });
+
+  it("skips the desktop section on web imports but keeps the editor payload", () => {
+    const result = parseSettingsTransferFile(fileWithSections({ appearance: { themeMode: "dark" }, desktop: { show_tray_icon: false }, editor: { wordWrap: true } }), { includeDesktopSettings: false });
+    expect(result.ok).toBe(true);
+    if (!result.ok) return;
+    expect(result.value.themeMode).toBe("dark");
+    expect(result.value.desktopSettings).toEqual({});
+    expect(result.value.editorSettings.wordWrap).toBe(true);
+    expect(result.value.categories).toContain("appearance");
+    expect(result.value.categories).not.toContain("other");
+  });
+
+  it("ignores a malformed desktop section on web imports", () => {
+    expect(parseSettingsTransferFile(fileWithSections({ desktop: [1], editor: { wordWrap: true } }), { includeDesktopSettings: false }).ok).toBe(true);
+    expect(parseSettingsTransferFile(fileWithSections({ desktop: { show_tray_icon: "yes" }, editor: { wordWrap: true } }), { includeDesktopSettings: false }).ok).toBe(true);
+  });
+
+  it("reports an empty import when a desktop-only file is read on web", () => {
+    const result = parseSettingsTransferFile(fileWithSections({ desktop: { show_tray_icon: false } }), { includeDesktopSettings: false });
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error.code).toBe("empty-settings");
+  });
 });
diff --git a/apps/desktop/src/lib/settings/settingsTransfer.ts b/apps/desktop/src/lib/settings/settingsTransfer.ts
index aa1303ee29..145c9d1f6c 100644
--- a/apps/desktop/src/lib/settings/settingsTransfer.ts
+++ b/apps/desktop/src/lib/settings/settingsTransfer.ts
@@ -1,5 +1,6 @@
 import { EDITOR_SETTINGS_DRAFT_KEYS, editorSettingsDraftFromSettings, type EditorSettingsDraftKey } from "./editorSettingsDraft";
-import { DEFAULT_CUSTOM_THEME_COLORS, DEFAULT_CUSTOM_THEME_DDL_COLORS, DEFAULT_EDITOR_SETTINGS, DEFAULT_TOOLBAR_ITEMS, normalizeEditorSettings, type EditorSettings } from "@/stores/settingsStore";
+import { DEFAULT_CUSTOM_THEME_COLORS, DEFAULT_CUSTOM_THEME_DDL_COLORS, DEFAULT_DESKTOP_SETTINGS, DEFAULT_EDITOR_SETTINGS, DEFAULT_TOOLBAR_ITEMS, normalizeDesktopSettings, normalizeEditorSettings, type DesktopSettings, type EditorSettings } from "@/stores/settingsStore";
+import type { AppThemeMode } from "@/lib/app/appTheme";
 import { EDITOR_MAX_FONT_SIZE, EDITOR_MIN_FONT_SIZE } from "@/lib/editor/editorZoom";
 import { DATA_GRID_TYPE_COLOR_KEYS, DATA_GRID_TYPE_COLOR_SCHEME_AUTO_ID } from "@/lib/dataGrid/dataGridTypeColorScheme";
 import { SHORTCUT_DEFINITIONS } from "@/lib/editor/shortcutRegistry";
@@ -10,10 +11,12 @@ import { SQL_VARIABLE_SYNTAX_KEYS } from "@/lib/sql/sqlVariableSyntax";
  * Local backup / restore of application settings ("配置导入与导出").
  *
  * The transfer file is a versioned JSON document with a strict field
- * whitelist: only dialog-managed editor settings are serialized. Connection
- * data, saved SQL libraries, AI configuration and device-specific paths are
- * never part of the payload, and unknown fields in an imported file are
- * ignored instead of being written into the draft.
+ * whitelist. The `settings.editor` section carries the dialog-managed editor
+ * settings; the optional `settings.appearance` and `settings.desktop`
+ * sections carry the app-wide theme mode and the preference-like desktop
+ * settings. Connection data, saved SQL libraries, AI configuration and
+ * device-specific paths are never part of the payload, and unknown fields in
+ * an imported file are ignored instead of being written anywhere.
  */
 
 export const SETTINGS_TRANSFER_FORMAT_VERSION = 1;
@@ -21,6 +24,48 @@ export const SETTINGS_TRANSFER_FORMAT_VERSION = 1;
 /** Upper bound for an import file; real settings files are a few dozen KB. */
 export const MAX_SETTINGS_TRANSFER_FILE_BYTES = 5 * 1024 * 1024;
 
+/**
+ * Preference-like `DesktopSettings` keys eligible for transfer. Device-
+ * specific paths (driver/plugin/agent/skill directories, saved-SQL sync dir)
+ * and the one-shot `close_action_prompted` flag are deliberately excluded:
+ * they are either meaningless on another machine or not a user preference.
+ */
+export const TRANSFERABLE_DESKTOP_SETTINGS_KEYS = [
+  "show_tray_icon",
+  "icon_theme",
+  "quit_on_close",
+  "debug_logging_enabled",
+  "metadata_cache_max_memory_mb",
+  "duckdb_worker_process_isolation",
+  "duckdb_worker_max_processes",
+  "sidebar_table_page_size",
+] as const satisfies readonly (keyof DesktopSettings)[];
+
+export type TransferableDesktopSettingsKey = (typeof TRANSFERABLE_DESKTOP_SETTINGS_KEYS)[number];
+
+/** The transferable keys without their `null` "unset" variants. */
+export type TransferableDesktopSettings = {
+  [K in TransferableDesktopSettingsKey]: Exclude<DesktopSettings[K], null>;
+};
+
+/** Non-editor sections carried alongside the editor draft in the transfer file. */
+export interface SettingsTransferExtras {
+  /** App-wide light/dark/system mode from `settings.appearance`. */
+  themeMode?: AppThemeMode;
+  /** Preference-like desktop settings from `settings.desktop`. */
+  desktopSettings?: Partial<TransferableDesktopSettings>;
+}
+
+/** Keeps only the whitelisted desktop keys, ignoring everything else. */
+export function pickTransferableDesktopSettings(settings: Partial<DesktopSettings>): Partial<TransferableDesktopSettings> {
+  const picked: Partial<TransferableDesktopSettings> = {};
+  for (const key of TRANSFERABLE_DESKTOP_SETTINGS_KEYS) {
+    const value = settings[key];
+    if (value !== undefined && value !== null) picked[key] = value as never;
+  }
+  return picked;
+}
+
 export type SettingsTransferCategoryId = "appearance" | "editor" | "formatter" | "navigation" | "data" | "shortcuts" | "snippets" | "other";
 
 export type SettingsTransferParseErrorCode = "too-large" | "invalid-json" | "unsupported-version" | "invalid-structure" | "empty-settings" | "invalid-fields";
@@ -37,9 +82,23 @@ export interface ParsedSettingsTransfer {
   exportedAt?: string;
   /** Validated, normalized values for exactly the keys present in the file. */
   editorSettings: Partial<EditorSettings>;
+  /** Validated theme mode from the optional appearance section. */
+  themeMode?: AppThemeMode;
+  /** Validated desktop preferences for exactly the keys present in the file. */
+  desktopSettings: Partial<TransferableDesktopSettings>;
   categories: SettingsTransferCategoryId[];
 }
 
+export interface SettingsTransferParseOptions {
+  /**
+   * Whether the platform-specific `settings.desktop` section applies. Web
+   * callers pass false: those switches are desktop-only, so the section is
+   * skipped the same way an older reader skips an unknown section — its
+   * values are neither validated nor listed among the importable categories.
+   */
+  includeDesktopSettings?: boolean;
+}
+
 export interface SettingsTransferExportMeta {
   appVersion?: string;
 }
@@ -55,14 +114,19 @@ export function buildSettingsTransferFilename(date = new Date()): string {
  * Serializes the saved editor settings into the transfer format. The draft
  * helper provides the whitelist, deep cloning and per-key normalization, so
  * the payload never contains fields outside `EDITOR_SETTINGS_DRAFT_KEYS`.
+ * The optional extras add the `appearance`/`desktop` sections; files written
+ * by older versions simply lack them.
  */
-export function serializeSettingsTransfer(settings: EditorSettings, meta: SettingsTransferExportMeta = {}): string {
+export function serializeSettingsTransfer(settings: EditorSettings, meta: SettingsTransferExportMeta = {}, extras: SettingsTransferExtras = {}): string {
+  const desktopSettings = extras.desktopSettings ? pickTransferableDesktopSettings(extras.desktopSettings) : {};
   const payload = {
     formatVersion: SETTINGS_TRANSFER_FORMAT_VERSION,
     app: { name: "dbx", ...(meta.appVersion ? { version: meta.appVersion } : {}) },
     exportedAt: new Date().toISOString(),
     settings: {
       editor: editorSettingsDraftFromSettings(settings),
+      ...(extras.themeMode ? { appearance: { themeMode: extras.themeMode } } : {}),
+      ...(Object.keys(desktopSettings).length > 0 ? { desktop: desktopSettings } : {}),
     },
   };
   return JSON.stringify(payload, null, 2);
@@ -571,7 +635,7 @@ const RAW_STRUCTURED_FIELD_VALIDATORS: Partial<Record<EditorSettingsDraftKey, (v
  * nested schema (see NESTED_FIELD_VALIDATORS): malformed nested payloads are
  * rejected instead of being silently repaired or persisted.
  */
-export function parseSettingsTransferFile(text: string): { ok: true; value: ParsedSettingsTransfer } | { ok: false; error: SettingsTransferParseError } {
+export function parseSettingsTransferFile(text: string, options: SettingsTransferParseOptions = {}): { ok: true; value: ParsedSettingsTransfer } | { ok: false; error: SettingsTransferParseError } {
   if (exceedsSettingsTransferSizeLimit(text)) {
     return { ok: false, error: { code: "too-large" } };
   }
@@ -592,17 +656,62 @@ export function parseSettingsTransferFile(text: string): { ok: true; value: Pars
   const settings = parsed.settings;
   if (!isPlainObject(settings)) return { ok: false, error: { code: "invalid-structure" } };
   const editor = settings.editor;
-  if (!isPlainObject(editor)) return { ok: false, error: { code: "empty-settings" } };
+  if (editor !== undefined && !isPlainObject(editor)) return { ok: false, error: { code: "invalid-structure" } };
+  const appearance = settings.appearance;
+  if (appearance !== undefined && !isPlainObject(appearance)) return { ok: false, error: { code: "invalid-structure" } };
+  const includeDesktop = options.includeDesktopSettings !== false;
+  const desktop = settings.desktop;
+  if (includeDesktop && desktop !== undefined && !isPlainObject(desktop)) return { ok: false, error: { code: "invalid-structure" } };
+
+  // App-wide theme mode from the optional appearance section. Only the three
+  // canonical modes are accepted; legacy soft-* values normalize before they
+  // ever reach a transfer file.
+  let themeMode: AppThemeMode | undefined;
+  if (isPlainObject(appearance) && appearance.themeMode !== undefined) {
+    const value = appearance.themeMode;
+    if (value === "light" || value === "dark" || value === "system") {
+      themeMode = value;
+    } else {
+      return { ok: false, error: { code: "invalid-fields", detail: "appearance.themeMode" } };
+    }
+  }
+
+  // Desktop preferences from the optional desktop section, skipped whole on
+  // platforms where the switches do not exist. Unknown keys are ignored like
+  // in the editor section; the accepted values must survive the store
+  // normalizer unchanged, so a clamped number (duckdb worker processes) or an
+  // out-of-domain enum (icon theme) rejects the whole file instead of being
+  // silently repaired.
+  const desktopKeys = includeDesktop && isPlainObject(desktop) ? TRANSFERABLE_DESKTOP_SETTINGS_KEYS.filter((key) => key in desktop) : [];
+  const importedDesktop: Partial<TransferableDesktopSettings> = {};
+  if (desktopKeys.length > 0 && isPlainObject(desktop)) {
+    const desktopProbe: Record<string, unknown> = { ...DEFAULT_DESKTOP_SETTINGS };
+    for (const key of desktopKeys) {
+      const raw = desktop[key];
+      if (typeof raw !== typeof DEFAULT_DESKTOP_SETTINGS[key]) {
+        return { ok: false, error: { code: "invalid-fields", detail: `desktop.${key}` } };
+      }
+      desktopProbe[key] = raw;
+    }
+    const normalizedDesktop = normalizeDesktopSettings(desktopProbe as Partial<DesktopSettings>);
+    for (const key of desktopKeys) {
+      if (normalizedDesktop[key] !== desktop[key]) {
+        return { ok: false, error: { code: "invalid-fields", detail: `desktop.${key}` } };
+      }
+      importedDesktop[key] = normalizedDesktop[key] as never;
+    }
+  }
 
   // Old exports used the inverse `dataGridAutoHideFilterBuilder` flag. Keep
   // accepting it, but normalize it into the single current preference before
   // applying the strict whitelist below.
-  if (!("dataGridKeepFilterEditorExpanded" in editor) && typeof editor.dataGridAutoHideFilterBuilder === "boolean") {
+  if (isPlainObject(editor) && !("dataGridKeepFilterEditorExpanded" in editor) && typeof editor.dataGridAutoHideFilterBuilder === "boolean") {
     editor.dataGridKeepFilterEditorExpanded = !editor.dataGridAutoHideFilterBuilder;
   }
 
-  const presentKeys = EDITOR_SETTINGS_DRAFT_KEYS.filter((key) => key in editor);
-  if (presentKeys.length === 0) return { ok: false, error: { code: "empty-settings" } };
+  const editorObject = isPlainObject(editor) ? editor : {};
+  const presentKeys = EDITOR_SETTINGS_DRAFT_KEYS.filter((key) => key in editorObject);
+  if (presentKeys.length === 0 && desktopKeys.length === 0 && themeMode === undefined) return { ok: false, error: { code: "empty-settings" } };
 
   // Validate the raw file values BEFORE the normalizer runs. Some store
   // normalizers assume well-formed containers (e.g. customThemes items must
@@ -611,7 +720,7 @@ export function parseSettingsTransferFile(text: string): { ok: true; value: Pars
   // rather than crashing the parse.
   const invalidKeys: string[] = [];
   for (const key of presentKeys) {
-    const raw = editor[key];
+    const raw = editorObject[key];
     if (jsonKindOf(raw) !== EXPECTED_JSON_KINDS.get(key)) {
       invalidKeys.push(key);
       continue;
@@ -630,13 +739,13 @@ export function parseSettingsTransferFile(text: string): { ok: true; value: Pars
   // mutated by a malformed file.
   const probe = deepClone(DEFAULT_EDITOR_SETTINGS) as EditorSettings;
   for (const key of presentKeys) {
-    (probe as unknown as Record<string, unknown>)[key] = editor[key];
+    (probe as unknown as Record<string, unknown>)[key] = editorObject[key];
   }
   const normalized = normalizeEditorSettings(probe);
 
   const imported: Partial<EditorSettings> = {};
   for (const key of presentKeys) {
-    const raw = editor[key];
+    const raw = editorObject[key];
     const value = (normalized as unknown as Record<string, unknown>)[key];
     const validator = PASS_THROUGH_FIELD_VALIDATORS[key] ?? NESTED_FIELD_VALIDATORS[key];
     if (validator && !validator(value)) {
@@ -673,6 +782,10 @@ export function parseSettingsTransferFile(text: string): { ok: true; value: Pars
   const rawAppVersion = typeof app.version === "string" ? app.version.trim() : "";
   const rawExportedAt = typeof parsed.exportedAt === "string" ? parsed.exportedAt : "";
 
+  const categories = new Set(collectTransferCategories(Object.keys(imported)));
+  if (themeMode !== undefined) categories.add("appearance");
+  if (desktopKeys.length > 0) categories.add("other");
+
   return {
     ok: true,
     value: {
@@ -680,7 +793,9 @@ export function parseSettingsTransferFile(text: string): { ok: true; value: Pars
       ...(rawAppVersion ? { appVersion: rawAppVersion } : {}),
       ...(rawExportedAt ? { exportedAt: rawExportedAt } : {}),
       editorSettings: imported,
-      categories: collectTransferCategories(Object.keys(imported)),
+      ...(themeMode !== undefined ? { themeMode } : {}),
+      desktopSettings: importedDesktop,
+      categories: sortTransferCategories(categories),
     },
   };
 }